As a technology of correcting angle information that has been detected by use of an angle detector, in one technology, for example, there is a technology described in patent literature 1. In this technology, an angle signal is detected from a signal detected by a resolver, the detected angle signal is differentiated for detecting a speed signal, and an error is estimated by use of the detected speed signal. Then, the speed signal is corrected by use of the estimated error and the corrected speed signal is integrated, so as to obtain the angle signal in which the error is corrected.